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Discussion Starter #1
Have put an AR15 together. My first with an A2 type front sight. The sight is HIGH. I have ordered a mil spec rear sight to mount on the flat top rail.

I want to mount an inexpensive red-dot scope. Problem is, the scope sits too low on the flat top piccatinny rail and the front sight totally obscures the sight picture because it is much taller than the red-dot field of vision. I would like to lift the red-dot with a riser. Two questions... first, is it better to have the point of air (red dot) coincide with the iron sight point of aim or is it better to have the red-dot point of aim OVER the iron sight point of aim? I think a 3/4" riser would have them coincide and a 1" would have the red-dot point of aim above the iron sights. Please help as I don't want to waste money and time buying the wrong riser. Thanks - wg

PS: Academy in San Antonio has 1" risers.
 

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i have a red dot mounted on my flattop A3, i removed the A2 front sight and installed a flip up front sight. that being said i have my red dot set where i can co-witness through the red dot with the iron sights. i have my red dot set right on top of my front sight post. first i zeroed my iron sights then set the red dot on top of front sight and it is dead on. with it set up that way i can shoot either with iron sights (co-witness) or fold the iron sights down and use just the red dot. the advantage of a setup this way is i can remove the red dot and reinstall and all i have to do set the dot on the front sight post and i know my red dot is dead on.
 

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I prefer absolute co-witness. Meaning that with my rear sight flipped up my red dot sits right on top of the front sight post with a proper sight picture.

This is what I recommend, as it's easy to re-zero either systems if you know the other is correct.

If your dot is off and your irons are on you can "lolli-pop" the red dot on the FSP with a proper sight picture and have a reasonable zero with the dot. Vice versa applies if your dot is on, but your irons are not, you can reposition your irons til the "lolli-pop" is again in effect.

What kind of dot are you using? My vortex SPARC came with enough mounts and shims to be able to mount it on anything from a shotgun to ak to AR with either lower 1/3 or absolute co-witness.
 

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Discussion Starter #4
I bought a cheapo Tasco red-dot from Walmart. I already have four other rifles I have purchased optics for so need to keep costs down. I have the Tasco on another rifle and it holds zero and has 12 different intensities so you can shoot accurately up to about 100 yards by varying the setting (I just got new glasses so there is hope I can see the target with no magnification at 100 yards).
 

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Another cheap strong alternative with several mounting solutions is a primary arms micro-dot. It's an aimpoint micro clone, costs about $80 and gets very strong reviews.
 

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I bought a cheapo Tasco red-dot from Walmart. I already have four other rifles I have purchased optics for so need to keep costs down. I have the Tasco on another rifle and it holds zero and has 12 different intensities so you can shoot accurately up to about 100 yards by varying the setting (I just got new glasses so there is hope I can see the target with no magnification at 100 yards).
I've got one of those Tasco's on top of my Hi-Point 995, definitely well worth the $30 at Walmart for it. I put a SightMark reflex sight that let's me put rifled slugs pretty much anywhere i want within 100 yards of an 18 1/2" Mossberg 500. That one cost me $40 at Dunham's, and seems to be on sale at that price all the time. Only saved .02 cents if i would have ordered from CTD, so i'm glad i saved the shipping by being out and about that day.
 

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Two questions... first, is it better to have the point of air (red dot) coincide with the iron sight point of aim or is it better to have the red-dot point of aim OVER the iron sight point of aim? I think a 3/4" riser would have them coincide and a 1" would have the red-dot point of aim above the iron sights.
Personally I think it's best to have the poa looking where the bullet is going at the range you'll be shooting at. With an AR15 and the high sights you're almost always a little high or a little low at different ranges due to the height of the sights and the trajectory of the bullet. Personally I prefer flip up front and rear sights, and I like them cowitnessed right on the money. I set my irons so the strike of the round occurs just on top of and centered on the front sight post when it's up and I'm looking through the ghost ring rear. Then I fold them down and there's just the red dot, and that way I don't have any part of a front sight obscuring the target area. And if you keep both eyes open with a red dot you'll find that it seems to project the dot out onto the target for really fast target acquisition and good peripheral vision. Which is the beauty of a red dot, IMHO. Might think about changing the front sight for a picatinny gas block and flip up sight. JAT
 

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i replaced my A2 front sight with a Yankee Hill flip up front sight that has a picatinny rail on the bottom. also the sight bolted into place no need to pin it in place,still had to pin gas tube into front sight.
 

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I have always thought that to co-witness the iron sights, like the ACOG that I used on my service weapons, the center of glass on a red dot sould be exactly in the middle when veiwing irons. The new school of thought is the bottom third or the top third. I think this is BS. Have you tried getting the UTG red/green dot from cheaper than dirt? I got one because it was only 50 bucks just to try it. It works great and comes with two mount bases. I have it on a RR flat top and it is exactly middle of the glass with the post front and rear flip up. I have a similar constructed sight that cost 300.00 bucks on a colt CAR15 from 1986 that will not co-witness that great no matter where I put it. See the pics I attached. Looking to get another UTG as maybe a sight for my M1 Carbine.
The UTG red/green dot is by the way model number is SCP-D53039W. It's a 30 mm tube..wish it was a 40 mm and belive it or not, that makes alot of difference. With a 40 mm you have more glass circumfrence to veiw the irons...but this 30 mm works great.... If you want to call and talk about it please do so..that goes for anyone if I can answer a question..if you want to here from some assclown 24 year vet of the Army..just retired in 2005...and if your cell has free long distance 425-622-1646 Oh..and remember that your front post is not too high..the optimum sight height for the AR platform is no more than 2.2 inches from the center line of the barrel. Scopes on a A1 or A2 are junk after 200 yards. That was a lesson learned by the Army when they authorised some civilian purchased scopes back in the late 80's...the whole reason we have flat tops now BTW.....It took a bunch of E3 and E4's to figure that out.
 

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j3 -

Mounting an optic on handguards is strongly discouraged, even if your handguards are free floated they will flex with pressure from your support hand or other outside factors, causing the optic to not maintain zero.

Try looking for a carry handle mount, your carry handle should have a hold in the middle of it less than 1/4" in diameter. The carry handle mount will snug down in there and goose neck your optic over your handguards. You will not be able to co-witness as far as I know.
 
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I know that. I was trying to mount in several posistions to see if it would co -witness...I posted that as an example. Just to take a picture. Goes back to the never over 2 inch from centerline of the barrel rule.
I never use the handguards..always a well grip. But at least it's nice too see somebody else who is in the "know"
That Colt has no optics on it, and the original plastic is stored in a safe box. The triangle short hand guards. :)
 

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I have always thought that to co-witness the iron sights, like the ACOG that I used on my service weapons, the center of glass on a red dot sould be exactly in the middle when veiwing irons. The new school of thought is the bottom third or the top third. I think this is BS. Have you tried getting the UTG red/green dot from cheaper than dirt? I got one because it was only 50 bucks just to try it. It works great and comes with two mount bases. I have it on a RR flat top and it is exactly middle of the glass with the post front and rear flip up. I have a similar constructed sight that cost 300.00 bucks on a colt CAR15 from 1986 that will not co-witness that great no matter where I put it. See the pics I attached. Looking to get another UTG as maybe a sight for my M1 Carbine.
The UTG red/green dot is by the way model number is SCP-D53039W. It's a 30 mm tube..wish it was a 40 mm and belive it or not, that makes alot of difference. With a 40 mm you have more glass circumfrence to veiw the irons...but this 30 mm works great.... If you want to call and talk about it please do so..that goes for anyone if I can answer a question..if you want to here from some assclown 24 year vet of the Army..just retired in 2005...and if your cell has free long distance 425-622-1646 Oh..and remember that your front post is not too high..the optimum sight height for the AR platform is no more than 2.2 inches from the center line of the barrel. Scopes on a A1 or A2 are junk after 200 yards. That was a lesson learned by the Army when they authorised some civilian purchased scopes back in the late 80's...the whole reason we have flat tops now
BTW.....It took a bunch of E3 and E4's to figure that out.
Might have to hit you up on that! Just picked up my first AR15 Bushmaster Carbine and looking for inexpensive optics for now. Figure what ever I eventually up grade can go on the AR22lr! My gunsmith is a big AR guy and he talks up the pricey stuff! Anywho 24 year Navy vet here! I am interested in something that I can co-witness and not break the bank. I think that UTG red dot you have can also be set up with their magnifier as well. Thanks Gene
 
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